Passive pure fluid component



June 29, 1965 R. E. BOWLES 3,191,623

PASSIVE PURE FLUID COMPONENT Filed Feb. 21, 1963 3,191,623 Patented June 29, 1965 United States Patent Office 3,191,623 PASSIVE PURE FLUID COMPONENT Romald E. Bowles, 12712 Meadowood Lane, Silver Spring, Md. Filed Feb. 21, 1963, Ser. No. 260,967

3 Claims. (Cl. 137-613) (Granted under Title35, US. Code (1952), sec. 266) The invention herein may be manufactured and used byor for the Government of the United States of America for governmental purposes without the payment to me of any royalty thereon. v V

This inventionrelates to fluid operated systems and, more particularly, to circuit elements therein such as diodes, time delay means, and pressure dividers.

In fluid operated systems, the combinationof subsystem circuits often requires additional circuit elements such as diodes, time delay means, pressure dividers and the like. In this invention, a passive pure fluid component is presented which exhibits diode characteristics in one use, is a time delay means when such delay is desired in a second use and will act as a pressure divider in a third use. The structure of the component provides an impedance to flow in one direction therethrough that is significantly different from the impedance to flow in the opposite direction thus operating as a diode. The combination of orifices and volume as a circuit constitutes an impedance which provides a phase shift during transient flow and so contributes to the retarding of fluid flow to introduce time delay characteristics. The pressure division is accomplished as a result of the ratio of flow area of a first orifice and a second orifice so that the pressure of a chamber therebetween will be a fixed percentage of the pressure in a chamber feeding said first orifice for flow in the direction first orifice toward the second orifice.

It is, therefore, an object of this invention to provide a component through which fluid flows with relatively low impedance in one direction and with a relatively higher impedance in the opposite direction.

Another object of this invention is to provide a fluid operated component which introduces phase shift and time delay to fluid flow thereto.

Still another object of this invention is to provide a fluid operated component which is capable of dividing by a fixed ratio the pressure of a fluid supplied thereto.

A further object of this invention is to provide a single fluid operated component having diode characteristics, time delay capabilities and fluid pressure dividing properties.

The specific nature of the invention, as well as other objects, uses, and advantages thereof, will clearly appear from the following description and from the accompanying drawing, in which:

The single figure shows the structure of this invention.

Briefly, this invention relies upon the tapering of a first conductor into a nozzle in such a manner that a minimum of impedance (consistent with available flow area) is presented to the fluid flowing through the passage and nozzle. The supply nozzle introduces the fluid into a cylindrical, for example, chamber which has a wall perpendicular to the nozzle where it issues fluid into the chamber and the downstream wall of the chamber is tapered to a second nozzle in such a manner that again minimum of impedance is presented to the fluid. The second nozzle is introduced into a second conductor through an end wall that is perpendicular to the second nozzle in the same manner that the first nozzle was introduced into the chamber. The nozzle discharge coeflicients for the nozzles are difierent for flow in the direction of the first conductor, the chamber and the second conductor nozzle discharge coefiicients for the opposite fluid flow in the opposite direction.

The single figure shows the structure of this invention with the entrance conductor 1 being bounded by sides 2 and tapering at 3 into a nozzle 4 of considerably smaller cross section than conductor 1. The relationship between the flow area of conductor 1 and the interior of nozzle 4 is in the order of 5:1. The conductor 1 can be tubular in cross section or any other desired configuration.

' Nozzle 4 introduces the fluid into a chamber 5. Nozzle 4 is perpendicular to a side 6 of chamber 5. If chamber 5 may be chosen to be a cylindrical configuration, the circular generation of sides 7 would provide confinement for the fluid introduced therein when the remaining portion of chamber 5 would be tapered as at corners 8 to a nozzle 9. The centerline of nozzle 9 is displaced from the centerline of nozzle 4 by a distance d. The relationship between the opening of nozzle 4 and the side 6 is of even greater magnitude than that of the entrance passage and nozzle 4. The particular ratio chosen depends upon the amount of eflectiveness desired. That is, the larger the ratio, the larger the impedance to flow and the converse is true.

The nozzle 9 enters a third section 10 through side 11 thereof into a chamber bounded by side 12 which may be cylindrical if desired. Chamber 10 can be the connecting passage to the rest of the fluid system requiring the device of this invention.

In the operation of this device, fluid entering chamber 1 will encounter less impedance in its flow through nozzle 4, chamber 5, nozzle 9 and chamber 10 than fluid flowing in the opposite direction. That is entering chamber 10 and flowing through nozzle 9, chamber 5, nozzle 4 and passage 1. This difference in impedance provides the diode eflect of ease of flow in one direction and deterrence to flow in the opposite direction.

The tapering of the ends of the chambers containing the fluid which is moving into a'nozzle and into the next chamber offers far less resistance to flow than the flat wall with a small hole in it encountered by fluid flow in the opposite direction. That is, the nozzle discharge coefficients are diflerent for the different directions of flow of fluids therethrough.

Nozzles 4 and 9 are offset so that the fluid will not simply continue through the chamber 5 as though it were a closed conductor. Turbulence and the associated vortices are present together with the volume of chamber 5 to provide time delay of a fluid signal therethrough.

As a time delay device, it is apparent that time is consumed in the passage of a fluid transient from chamber 1 through the nozzles and chamber 5 into chamber 10. More time is required during the reverse passage of such a fluid transient.

As a pressure divider, the ratio of pressure between the input and the output is a function of the ratio of sizes of the orifices in the nozzles. By selecting the size of the openings between chambers 1 and 5 and return chamber 5 and 10 and by operating this circuit such that these orifices both operate when choked, that is, at the speed of sound the pressure in chamber 5 will be a fixed fraction of the pressence in chamber 1 for the steady state condition. The pressure in chamber 5 divided by the pressure in chamber 1 is equal to a constant for a steady state condition of a diabatic flow.

As a diode, this unit has a different (lower) resistance to flow in the direction 1-5-10 than the resistance to flow in the opposite direction 10-5-1. This unit will exhibit a higher flow in the direction 1-5-10 when an alternating pressure is superimposed on a steady state positive pressure (dP), where (dP) equals the difference in pressures between chambers 1 and 10 than when the difference pressure is steady state at the same averagevalue. When the positive difference pressure (a'P) equals pressure in chamber 10 minus the pressure in chamber 1, the flow will be in the direction 105-1 and will be of lower amplitude than for an equal pressure drop (dP) of opposite sense with or without the alternating pressure superimposed.

It will be apparent that the embodiment shown is only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

I claim as my invention:

1. A fluid-operated component comprising a fluid chamber, a passage for fluid, a first nozzle for directing fluid under pressure from said first passage into said fluid chamber, a second passage for fluid, a second nozzle for directing fluid from said fluid chamber to said second passage; the diameters of said nozzles being such that sonic flow velocities are maintained'in said first and said second nozzles.

2. The combination according to claim 1 wherein said nozzles are shaped to present a relatively low impedance to flow in a direction from said first passage to said sec- 0nd passage and a relatively high impedance to flow in the reverse direction.

3. The combination according to claim 1 wherein the centerlines of said nozzles are offset by more than the diameter of the larger nozzle.

References Cited by the Examiner UNITED STATES PATENTS 1,874,326 8/32 Mason 18l47 2,322,026 6/43 Jaeckel 13842 XR 2, 19,124 1 1 52 Bertin 13s 42 2,664,109 12/53 Iager 13s 42 2,856,962 10/58 Christoph 138-42 FOREIGN PATENTS 683,692 3/30 France.

141,254 4/20 Great Britain- 228,278 1 1/43 Switzerland.

M. CARY NELSdN, Primary Examiner. 

1. A FLUID-OPERATED COMPONENT COMPRISNG A FLUID CHAMBER, A PASSAGE FOR FLUID, A FIRST NOZZLE FOR DIRECTING FLUID UNDER PRESSURE FROM SAID FIRST PASSAGE INTO SAID FLUID CHAMBER, A SECOND PASSAGE FOR FLUID, A SECOND NOZZLE FOR DIRECTING FLUID FROM SAID FLUID CHAMBER TO SAID SECOND PASSAGE, THE DIAMETERS OF SAID NOZZLES BEING SUCH THAT SONIC FLOW VELOCITIES ARE MAINTAINED IN SAID FIRST AND SAID SECOND NOZZLES. 